Bars translated orthogonally to their axis by worm screws or similar devices, which tend to differentiate and separate the position of one bar with respect to the adjacent bar, may often find themselves in a position where they may twist and overlap.
This may happen either because one bar falls or because the separator means do not intervene correctly.
This problem is particularly serious at the outlet of rolling processes where thin diameters are worked.
Translating one bar at a distance from the next is a necessary factor if the bars are to be counted correctly.
If two bars travel orthogonally together, counting means such as are known to the art do not give a univocal figure, and certainly do not guarantee that the phenomenon will be correctly identified.
This means that, as the pack is formed, more bars are introduced therein than the number counted, which creates both management problems and considerable economic problems.
This invention therefore has the purpose of achieving a selection and control device for bars which will make it possible to univocally identify whether there is a single bar in transit, or two or more bars travelling adjacent inside a single seating of the translation means, and which therefore cannot be individually recognised by the counting means.
JP-A-03002993 teaches to use two optical detectors to count bars moving on a plane.
The optical detectors are suitable to prevent counting mistakes caused by any possible inclination or mis-alignment of the bars, and to distinguish the direction of feed, either forwards or backwards, of the bars.
The optical detectors disclosed in JP'993, however, are not suitable to recognise and ascertain the presence of one or more bars in a single seating of the translation means, or to possibly provide information on the number of bars which can be found, erroneously, positioned in one seating of the said translation means.
In order to solve this deficiency in the state of the art, the present Applicant has designed and tested this invention.